Comprehension Questions

Section 25.1

Question 25.1

What is a Mendelian population? How is the gene pool of a Mendelian population usually described?

Section 25.2

Question 25.2

What are the predictions given by the Hardy–Weinberg law?

Question 25.3

What assumptions must be met for a population to be in Hardy–Weinberg equilibrium?

Question 25.4

What is random mating?

Question 25.5

Give the Hardy–Weinberg expected genotypic frequencies for (a) an autosomal locus with three alleles, and (b) an X-linked locus with two alleles.

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Section 25.3

Question 25.6

Define inbreeding and briefly describe its effects on a population.

Section 25.4

Question 25.7

What determines the allelic frequencies at mutational equilibrium?

Question 25.8

What factors affect the magnitude of change in allelic frequencies due to migration?

Question 25.9

Define genetic drift and give three ways in which it can arise. What effect does genetic drift have on a population?

Question 25.10

What is effective population size? How does it affect the amount of genetic drift?

Question 25.11

Define natural selection and fitness.

Question 25.12

Briefly describe the differences between directional selection, overdominance, and underdominance. Describe the effect of each type of selection on the allelic frequencies of a population.

Question 25.13

What factors affect the rate of change in allelic frequency due to natural selection?

Question 25.14

Compare and contrast the effects of mutation, migration, genetic drift, and natural selection on genetic variation within populations and on genetic divergence between populations.

For more questions that test your comprehension of the key chapter concepts, go to for this chapter.